The invention is in the field of visible fault locators used to locate faults in optical waveguides with the use of a laser. Such fault locators package a laser producing light in the visible range coupled to a common fiber optic connector. The package is connected to an optical waveguide or a cabled optical waveguide terminated with a similar connector. When the unit is turned on, the laser light is emitted into a waveguide. The user can observe a visible glow at a location where there is a break or microbend in a waveguide, even one having a jacket.
Some visible fault locators operate in a modulation mode of one or two Hz at a fifty percent (50%) duty cycle; this means that power is emitted in an on-off fashion during transmission, at a ratio of on fifty percent (50%) of the time and off fifty percent (50%) of the time. A one or two Hz frequency produces a light which visibly pulses in a manner like a flashing neon sign. Other visible fault locators shine continuously; many operators seem to prefer working with a continuous beam.
While visible fault locators allow fast cable inspections, their major disadvantage is the inherent danger to the eye posed by direct exposure to laser radiation. This danger persists even at a fifty percent (50%) duty cycle, which reduces optical output power by half. Therefore, a locator is needed which satisfies the desire for a continuous beam and maintains brightness while minimizing optical power output, reducing a serious health occupational safety hazard and incidentally increasing battery life.